The standard INSTALL file included in the source distribution

Installation instructions for OpenVPN, a Secure Tunneling Daemon
Copyright (C) 2002-2010 OpenVPN Technologies, Inc. This program is free software;
you can redistribute it and/or modify
it under the terms of the GNU General Public License version 2
as published by the Free Software Foundation.
*************************************************************************
QUICK START:
Unix:
./configure && make && make-install
Cross-compile for Windows on Unix
See INSTALL-win32.txt
*************************************************************************
To download OpenVPN, go to:
https://openvpn.net/community-downloads/
OpenVPN releases are also available as Debian/RPM packages:
https://community.openvpn.net/openvpn/wiki/OpenvpnSoftwareRepos
To download easy-rsa go to:
https://github.com/OpenVPN/easy-rsa
To download tap-windows driver source code go to:
https://github.com/OpenVPN/tap-windows
To get the cross-compilation environment go to:
https://github.com/OpenVPN/openvpn-build
For step-by-step instructions with real-world examples see:
https://openvpn.net/community-resources/how-to/https://community.openvpn.net/openvpn/wiki
For examples see:
https://openvpn.net/examples.html
Also see the man page for more information, usage examples, and information on
firewall configuration.
*************************************************************************
SUPPORTED PLATFORMS:
(1) Linux (kernel 2.6+)
(2) Solaris
(3) OpenBSD 5.1+
(4) Mac OS X Darwin 10.5+
(5) FreeBSD 7.4+
(6) NetBSD 5.0+
(7) Windows (WinXP and higher)
SUPPORTED PROCESSOR ARCHITECTURES:
In general, OpenVPN is word size and endian independent, so
most processors should be supported. Architectures known to
work include Intel x86, Alpha, Sparc, Amd64, and ARM.
REQUIRES:
(1) TUN and/or TAP driver to allow user-space programs to control
a virtual point-to-point IP or Ethernet device. See
TUN/TAP Driver Configuration section below for more info.
OPTIONAL (but recommended):
(1) OpenSSL library, necessary for encryption, version 0.9.8 or higher
required, available from https://www.openssl.org/
(2) PolarSSL library, an alternative for encryption, version 1.1 or higher
required, available from https://polarssl.org/
(3) LZO real-time compression library, required for link compression,
available from https://www.oberhumer.com/opensource/lzo/
OpenBSD users can use ports or packages to install lzo, but remember
to add CFLAGS="-I/usr/local/include" LDFLAGS="-L/usr/local/lib"
directives to "configure", since gcc will not find them otherwise.
OPTIONAL (for developers only):
(1) Autoconf 2.59 or higher + Automake 1.9 or higher
-- available from https://www.gnu.org/software/software.html
(2) Dmalloc library
-- available from https://dmalloc.com/
*************************************************************************
CHECK OUT SOURCE FROM SOURCE REPOSITORY:
Clone the repository:
git clone https://github.com/OpenVPN/openvpn
git clone git://openvpn.git.sourceforge.net/gitroot/openvpn/openvpn
Check out stable version:
git checkout -b 2.2 remotes/origin/release/2.2
Check out master (unstable) branch:
git checkout master
*************************************************************************
BUILD COMMANDS FROM TARBALL:
./configure
make
make install
*************************************************************************
BUILD COMMANDS FROM SOURCE REPOSITORY CHECKOUT:
autoreconf -i -v -f
./configure
make
make install
*************************************************************************
BUILD A TARBALL FROM SOURCE REPOSITORY CHECKOUT:
autoreconf -i -v -f
./configure
make dist
*************************************************************************
TESTS (after BUILD):
make check (Run all tests below)
Test Crypto:
./openvpn --genkey --secret key
./openvpn --test-crypto --secret key
Test SSL/TLS negotiations (runs for 2 minutes):
./openvpn --config sample/sample-config-files/loopback-client (In one window)
./openvpn --config sample/sample-config-files/loopback-server (Simultaneously in another window)
For more thorough client-server tests you can configure your own, private test
environment. See tests/t_client.rc-sample for details.
*************************************************************************
OPTIONS for ./configure:
--disable-lzo disable LZO compression support [default=yes]
--enable-lzo-stub don't compile LZO compression support but still
allow limited interoperability with LZO-enabled
peers [default=no]
--disable-crypto disable crypto support [default=yes]
--disable-ssl disable SSL support for TLS-based key exchange
[default=yes]
--enable-x509-alt-username
enable the --x509-username-field feature
[default=no]
--disable-multi disable client/server support (--mode server +
client mode) [default=yes]
--disable-server disable server support only (but retain client
support) [default=yes]
--disable-plugins disable plug-in support [default=yes]
--disable-eurephia disable support for the eurephia plug-in
[default=yes]
--disable-management disable management server support [default=yes]
--enable-pkcs11 enable pkcs11 support [default=no]
--disable-socks disable Socks support [default=yes]
--disable-http-proxy disable HTTP proxy support [default=yes]
--disable-fragment disable internal fragmentation support (--fragment)
[default=yes]
--disable-multihome disable multi-homed UDP server support (--multihome)
[default=yes]
--disable-port-share disable TCP server port-share support (--port-share)
[default=yes]
--disable-debug disable debugging support (disable gremlin and verb
7+ messages) [default=yes]
--enable-small enable smaller executable size (disable OCC, usage
message, and verb 4 parm list) [default=yes]
--enable-password-save allow --askpass and --auth-user-pass passwords to be
read from a file [default=yes]
--enable-iproute2 enable support for iproute2 [default=no]
--disable-def-auth disable deferred authentication [default=yes]
--disable-pf disable internal packet filter [default=yes]
--enable-strict enable strict compiler warnings (debugging option)
[default=no]
--enable-pedantic enable pedantic compiler warnings, will not generate
a working executable (debugging option) [default=no]
--enable-strict-options enable strict options check between peers (debugging
option) [default=no]
--enable-selinux enable SELinux support [default=no]
--enable-systemd enable systemd suppport [default=no]
ENVIRONMENT for ./configure:
IFCONFIG full path to ipconfig utility
ROUTE full path to route utility
IPROUTE full path to ip utility
NETSTAT path to netstat utility
MAN2HTML path to man2html utility
GIT path to git utility
TAP_CFLAGS C compiler flags for tap
OPENSSL_CRYPTO_CFLAGS
C compiler flags for OPENSSL_CRYPTO, overriding pkg-config
OPENSSL_CRYPTO_LIBS
linker flags for OPENSSL_CRYPTO, overriding pkg-config
OPENSSL_SSL_CFLAGS
C compiler flags for OPENSSL_SSL, overriding pkg-config
OPENSSL_SSL_LIBS
linker flags for OPENSSL_SSL, overriding pkg-config
POLARSSL_CFLAGS
C compiler flags for polarssl
POLARSSL_LIBS
linker flags for polarssl
LZO_CFLAGS C compiler flags for lzo
LZO_LIBS linker flags for lzo
PKCS11_HELPER_CFLAGS
C compiler flags for PKCS11_HELPER, overriding pkg-config
PKCS11_HELPER_LIBS
linker flags for PKCS11_HELPER, overriding pkg-config
*************************************************************************
BUILDING ON LINUX 2.6+ FROM RPM
You can build a binary RPM directly from the OpenVPN tarball file:
rpmbuild -tb [tarball]
This command will build a binary RPM file and place it in the system
RPM directory. You can then install the RPM with the standard RPM
install command:
rpm -ivh [binary-rpm]
When you install the binary RPM, it will install
sample-scripts/openvpn.init, which can be used to
automatically start or stop one or more OpenVPN tunnels on system
startup or shutdown, based on OpenVPN .conf files in /etc/openvpn.
See the comments in openvpn.init for more information.
Installing the RPM will also configure the TUN/TAP device node
for linux 2.6.
Note that the current openvpn.spec file, which instructs the rpm tool
how to build a package, will build OpenVPN with all options enabled,
including OpenSSL, LZO, and pthread linkage. Therefore all of
these packages will need to be present prior to the RPM build, unless
you edit the openvpn.spec file.
*************************************************************************
TUN/TAP Driver Configuration:
* Linux 2.6 or higher (with integrated TUN/TAP driver):
(1) load driver: modprobe tun
(2) enable routing: echo 1 > /proc/sys/net/ipv4/ip_forward
Note that (1) needs to be done once per reboot. If you install from RPM (see
above) and use the openvpn.init script, these steps are taken care of for you.
* FreeBSD:
FreeBSD ships with the TUN/TAP driver, and the device nodes for tap0,
tap1, tap2, tap3, tun0, tun1, tun2 and tun3 are made by default.
However, only the TUN driver is linked into the GENERIC kernel.
To load the TAP driver, enter:
kldload if_tap
See man rc(8) to find out how you can do this at boot time.
The easiest way is to install OpenVPN from the FreeBSD ports system,
the port includes a sample script to automatically load the TAP driver
at boot-up time.
* OpenBSD:
OpenBSD has dynamically created tun* devices so you only need
to create an empty /etc/hostname.tun0 (tun1, tun2 and so on) for each tun
you plan to use to create the device(s) at boot.
* Solaris:
You need a TUN/TAP kernel driver for OpenVPN to work:
https://www.whiteboard.ne.jp/~admin2/tuntap/
* Windows XP/2003/Vista/7:
OpenVPN on Windows needs a TUN/TAP kernel driver to work. OpenVPN installers
include this driver, so installing it separately is not usually required.
The driver source code is available here:
https://github.com/OpenVPN/tap-windows
*************************************************************************
CAVEATS & BUGS:
* I have noticed cases where TCP sessions tunneled over the Linux
TAP driver (kernel 2.4.21 and 2.4.22) stall when lower --mssfix
values are used. The TCP sessions appear to unstall and resume
normally when the remote VPN endpoint is pinged.
* If run through a firewall using OpenBSDs packet filter PF and the
filter rules include a "scrub" directive, you may get problems talking
to Linux hosts over the tunnel, since the scrubbing will kill packets
sent from Linux hosts if they are fragmented. This is usually seen as
tunnels where small packets and pings get through but large packets
and "regular traffic" don't. To circumvent this, add "no-df" to
the scrub directive so that the packet filter will let fragments with
the "dont fragment"-flag set through anyway.
* Mixing OFB or CFB cipher modes with static key mode is not recommended,
and is flagged as an error on OpenVPN versions 1.2.1 and greater.
If you use the --cipher option to explicitly select an OFB or CFB
cipher AND you are using static key mode, it is possible that there
could be an IV collision if the OpenVPN daemons on both sides
of the connection are started at exactly the same time, since
OpenVPN uses a timestamp combined with a sequence number as the cipher
IV for OFB and CFB modes. This is not an issue if you are
using CBC cipher mode (the default), or if you are using OFB or CFB
cipher mode with SSL/TLS authentication.

The openvpn.spec files

The OpenVPN 2.3 source tree contains an example RPM spec file under the distro subdirectory. For OpenVPN releases we use other spec files tailored for each supported operating system.